In a compression ratio variable device that is capable of varying the compression ratio by changing the combustion chamber volume of the internal combustion engine according to the rotational position of the control shaft, Japanese Patent Application Publication 2006-226133 discloses a structure in which rotation of the control shaft is limited by bringing a control-shaft-side stopper member, which is fixed on the control shaft, into abutment against a body-side stopper member, which is fixed on the cylinder block.
For example, in a structure to limit rotation of the control shaft by bringing a stopper surface of the body-side stopper member into abutment against a stopper surface of the control-shaft-side stopper member, there occurs a change of the position where the control-shaft-side stopper member is brought into abutment against the body-side stopper member, depending on variation of the control-shaft-side and body-side stopper members' shapes etc.
Herein, when the control-shaft-side stopper member has been brought into abutment against the body-side stopper member, provided that the rotational torque of the control shaft is constant, loads generated on both become greater as their abutment occurs at a position closer to the rotation center of the control shaft, when viewed in the axial direction of the control shaft.
That is, depending on variation of the body-side and control-shaft-side stopper members' shapes etc., the control-shaft-side stopper member is brought into a one-sided abutment against the body-side stopper member at a position that is relatively close to the rotation center of the control shaft when viewed in the axial direction of the control shaft, thereby causing a risk that a load to be generated on both of the body-side stopper member and the control-shaft-side stopper member becomes relatively large.
An internal combustion engine of the present invention has a variable compression ratio mechanism that is capable of continuously varying compression ratio of the internal combustion engine according to the rotational position of the control shaft, and a body-side stopper that limits rotation of the control shaft. The control shaft is equipped with a control-shaft-side stopper that is brought into abutment against the body-side stopper. The control-shaft-side stopper has a control-shaft-side stopper surface that is brought into abutment against the body-side stopper. The body-side stopper has a body-side stopper surface that is brought into abutment against the control-shaft-side stopper. When the control-shaft-side stopper is brought into abutment against the body-side stopper, the distance between the body-side stopper surface and the control-shaft-side stopper surface is configured to become longer on the control shaft rotation center side when viewed in the axial direction of the control shaft.
According to the present invention, even if both of the body-side stopper surface and the control side stopper surface have variation in their shapes etc., when the control-shaft-side stopper surface is brought into abutment against the body-side stopper surface, it is possible to prevent the control-shaft-side stopper surface from being brought into abutment against the body-side stopper surface at a position that is relatively close to the control shaft rotation center, when viewed in the axial direction of the control shaft. Therefore, it is possible to prevent loads, which are generated on both of the body-side stopper portion and the control-shaft-side stopper portion, from becoming relatively large, when the control-shaft-side stopper portion has been brought into abutment against the body-side stopper portion.